diff --git a/crates/bevy_pbr/src/render/mesh_vertex_output.wgsl b/crates/bevy_pbr/src/render/mesh_vertex_output.wgsl
index 32418f8043a7f..6cf70d2d17450 100644
--- a/crates/bevy_pbr/src/render/mesh_vertex_output.wgsl
+++ b/crates/bevy_pbr/src/render/mesh_vertex_output.wgsl
@@ -16,6 +16,6 @@ struct MeshVertexOutput {
     @location(4) color: vec4<f32>,
     #endif
     #ifdef VERTEX_OUTPUT_INSTANCE_INDEX
-    @location(5) instance_index: u32,
+    @location(5) @interpolate(flat) instance_index: u32,
     #endif
 }